In which type of contraction does the muscle lengthen while exerting force?

Eccentric contraction occurs when a muscle lengthens while still exerting force. This type of contraction is significant during activities that involve deceleration, such as when lowering weights or controlling movements against gravity. During an eccentric contraction, although the muscle is generating tension, it is unable to overcome the external force completely, resulting in the elongation of the muscle fibers.

For example, when performing a bicep curl and lowering the dumbbell, the bicep muscle lengthens as it controls the descent of the weight. This action is critical for joint stability and helps in absorbing shock during high-impact activities, ultimately contributing to muscle strength and coordination over time.

In contrast, isometric contractions occur when muscles generate force without changing length, concentric contractions involve shortening of the muscle while exerting force, and static contraction refers to a muscle remaining in a fixed position. Each of these types has its distinct characteristics and applications in strength training and rehabilitation but does not involve the lengthening of a muscle under tension like in eccentric contractions.